1. Field of the Invention
This invention relates to an apparatus for monitoring a bioluminescence of a biological sample, and especially relates to an apparatus for monitoring a bioluminescence of a biological sample wherein a monitoring part and a control part are separated from each other.
2. Description of Related Art
In various organisms, all genome sequences are successively determined, and the importance on a cyclopaedically functional analysis of a genome based on genome information is increasing. As an effective method of the genome functional analysis are used a DNA array method and a proteomix method. In these methods, however, it is impossible to conduct functional analysis of all genes because the detection sensitivity is low. Also, it is required to destroy a cell in these methods because an experiment is carried out by using mRNA or protein as a material.
A method of monitoring a bioluminescence in real time (Kondo et al., 1993, Proc Natl Acad Sci USA, Vol. 90, p 5672-5676; Millar et al., 1992, Plant Cell, Vol. 4, p 1075-1087) is an epoch-making non-destructive measuring method capable of monitoring a gene expression in high sensitivity and accuracy without destroying a cell. This method of monitoring a bioluminescence in real time is a key method of cyclopaedically analyzing the genome function.
Heretofore, a scintillation counter used for monitoring a radiation is utilized in the monitoring of the bioluminescence. This method utilizing the scintillation counter adopts a stacker system wherein plural 96-well plates for putting a biological sample into each well are vertically stacked on a plate-setting portion of the monitoring apparatus with an exclusive guide. That is, according to this method, when plant-based biological samples requiring a light for their growing are monitored, plates including the sample and transparent plates including no sample are stacked alternately and a light is applied from their side faces (Strayer et al., 2000, Science, Vol. 289, p 768-771).
As this method is further explained, two stackers are first provided, and the plates including the sample and the transparent plates including no sample are alternately stacked in one of the stackers as previously mentioned and the other stacker is kept at an empty state containing no plate. In the monitoring of the luminescence form the plant-based biological samples requiring a light for their growing, a light is irradiated from their side faces, whereby the light is irradiated to the plate to be tested from a space formed between the transparent plates.
The monitoring is carried out by taking out a bottom plate from the stacked plates and feeding into a measuring dark-room, and the plate after the monitoring is moved into a bottom of the other stacker, and then the monitoring of a newly bottom plate in the stacked plates of the stacker is carried out. After the monitoring of all plates is completed, these plates are taken out from the bottom of the stacker containing the measured plates and returned to the stacker having no plates to be tested in turn to render into a state prior to the monitoring. The monitoring is carried out by repeating the above procedure. Since a temperature is raised by the light source near to the plates, the problem of raising the temperature is somewhat mitigated by blowing air to the batch of the plates stacked through a fan.
In the bioluminescence monitoring of blue-green bacterium, a large scale apparatus of monitoring the bioluminescence is developed by Kondo and Ishiura, whereby a fully automatic monitoring of the bioluminescence on a large number of test samples is attained at a time (Kondo et al., 1994, Journal of Bacteriology, Vol. 176, p 1881-1885; Kondo et al., 1994, Science, Vol. 266, p 1233-1236). In this apparatus, since a chilled CCD camera is used for monitoring the bioluminescence, the monitoring sensitivity is low as compared with the use of the scintillation counter.
In the above method using the scintillation counter, however, it has been confirmed that an amount of light irradiated to each plate and an amount of light irradiated into each well within the plate are very non-uniform and the cultivation becomes non-uniform and hence a large scattering is caused in the monitored result. Also, it has been confirmed that since it is necessary to approach the light source to the sample for ensuring the amount of the light required for the growth, water included in the material to be tested is dewed in an inside of a seal attached to the plate by heat generated from the light source to largely scatter the monitored result. Further, it has been confirmed that the comparison and investigation of data every experience are not easy because the monitoring number per unit time changes as the number of the plates to be tested changes.
The apparatus for monitoring the bioluminescence of the samples is especially adaptable to a method for monitoring the bioluminescence in real time wherein the variation of the gene expression in a living cell of an organism incorporated with an emission gene is continuously monitored. This real-time method is an experiment method considerably effective for cyclopaedically separating a mutant related to the control of expression of any key gene, which is a powerful card for a cyclopaedical genome function analysis in the post-genomic era. Up to now, however, there is not developed an apparatus utilizing the merits of the real-time method to the utmost to cope with the large-scale monitoring.
Although the scintillation counter is generally used in the monitoring of the luminescence of organism samples, it is difficult to monitor plant-based organism samples under uniform growth cultivating conditions (especially, the light condition) because the light is required for the growth.
In the method of combining the sample cultivating and transferring apparatus and the scintillation counter, a large space is required for setting the apparatus and the cost becomes high. Moreover, since a control computer included in the scintillation counter is weak to a high temperature, the monitoring could be only carried out under a temperature environment of 15-35° C.